PROJECT SUMMARY Cancers of the head and neck (oral cavity, pharynx, and larynx) are the 5th most common cancers worldwide. Trans-oral surgical approaches such as trans-oral robotic surgery (TORS) and trans-oral laser microsurgery (TLM) are effective, reducing complications and long-term treatment morbidity. One of the drawbacks of the trans-oral approach is the difficulty in intraoperatively assessing tumor extent and locating critical vascular structures, resulting in positive margins and risks of vascular complications. Image guidance and surgical navigation play a significant role in sinus, skull base, and neurosurgery, demonstrating improvement in the safety and efficacy of these procedures. There may be advantages to applying this technology to trans-oral surgery for improved assessment of tumor depth and avoidance of vascular structures. Image guidance is currently not feasible for trans-oral robotic surgery. The main reason is the significant intraoperative tissue deformation that occurs with the introduction of retractors needed to provide surgical access. This intraoperative deformation limits the ability to accurately register preoperative imaging to the intra-operative state. With the availability of intra-operative CT and MRI imaging at Dartmouth?s unique Center for Surgical Innovation, intra-operative imaging is feasible. However, current instrumentation required for exposure and airway management during trans-oral robotic surgery creates significant artifact on CT imaging. We have developed a novel 3D printed polymer laryngoscope that enables us to safely acquire artifact free images of patients during laryngoscopy-based trans-oral surgery procedures and are now proposing to develop a similar CT-compatible retractor system for use in robotic procedures and to explore the development of a surgical navigation framework for TORS. The overarching goal of our efforts is to improve the safety and efficacy of trans-oral robotic surgery and enable surgeons to perform surgery on more complex cases through the use of surgical navigation. To achieve this goal, we propose to explore image guidance for trans-oral robotic surgery in two distinct phases: 1) development and validation of a CT-compatible retractor and instrument tracking to facilitate intraoperative imaging and surgical navigation and 2) comparison of conventional TORS and image- guided TORS (igTORS) in the resection of faux tumor models embedded in the base of tongue, larynx, and tonsils of cadaver heads. Importantly, this igTORS framework will be implemented through use of clinically standard navigation systems typically used for neurosurgical navigation (i.e. Medtronic?s StealthStation); this will help us to translate this framework more quickly to the bedside than had we developed a custom navigation system. By the end of this program we expect to have developed the framework for a fully integrated surgical guidance system for use in trans-oral robotic surgery. Follow on studies will be proposed to evaluate the efficacy of this framework in a clinical population of patients undergoing TORS.